Automatic fluid-pressure brake.



Patented Feb. 25, I902.

I w. H. CLARKE.

AUTOMATIC FLUID PRESSURE BRAKE.

(Application filed Kay 24, 1899. Renewed May 21, 1901.) I

(No Model.)

WITNESSES:

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.nish an improved form of that part of stand- UNITED STATES PATENT OFFIWILLIAM H. CLARKE, OF BROOKLYN, NEW YORK.

AUTOMATIC FLUID-PRESSURE BRAKE.

SPECIEILGATION forming part at Letters Patent No. 693,949, datedFebruary 25,1902. Application filed May 24, 1899. Renewed May 21, 1901.erial No. 61,317. (No model.)

To all w/wmit mag/concern.-

Be it known that L'VVILLIAM H. CLARKE,

lyn and State of New York, have invented certain new and usefulImprovements in Automatic Fluid-Pressure Brakes, of which the followingis a full, clear, and exact description.

This invention relates to automatic fluidpressure railway-brakes. Itsobject is to furard braking apparatus known as the quickaction triplevalve, the function of which in the usual practice of the art is togovern the ingress and egress of fluid-pressure to and from theauxiliary reservoir and brake-cylinder and to cause a quick serialventing of the train-pipe when sudden or emergency ap-.

plications of the brakes are desired. Such emergency venting of thetrain pipe discharges a part of its pressure either into thebrake-cylinder or into the atmosphere inthe common practice. Thequick-acting triple valve herein shown and described is ofatmospheric-vent variety, but may be readily adapted without alterationof any of its .principal parts to the discharge of fluid-pressu re intothe brake-cylinder in emergencies.

My invention is fully set forth in the accompanying drawings, in which'-Figure 1 represents a section of the improved valve, a portion of theauxiliary reservoir, and a portion of the pipe leading to thebrake-cylinder; and Fig. 2 is a detail of a modification.

The reservoir and cylinder are of wellknown construction and need not bedescribed herein.

A is the casing containing that part of the valve commonly known as theservicevalve, said service-valve being indicated by a and operated bythe piston or, carrying the graduating-valve a The application andrelease of brakes in the ordinary or service manner are elfected bythese parts in the same way as in the well-known Westinghouse triplevalve and need not be described at length. The head a carries a flange aupon which the spring a impinges, which parts serve to check themovement of piston a at the proper point in service applications of thebrakes and to limit itsfurther movement in emergency applications.

a is a release-port, and a is a port in the valve used in emergencyapplications.

Bis the casing of the emergency-piston 19, carrying the stem b andslide-valve b and held in normal position by spring 19 b is theemergency exhaust-port leading to the atmosphere. The train-pipeconnection is made at 19 V C is the auxiliary reservoir. c is a portconnecting the service-valve casing or chamber A with that portion ofchamber B above the emergency-piston b. v

' D is the brake-cylinder, pipe, and d the port connecting it with theservice-valve chamber All parts are shown in normal position. In makingwhat is known as a service application, the train-pipe, valve-chambers,

and auxiliary reservoir being charged to normal pressure of, say,seventy pounds per square inch, train-pipe pressure is reduced from fiveto seven pounds, whereupon the excess pressure to the left of piston aforces it against the head or stop a unseating graduatingvalve a andalining its port with brake-cylinder port at. This will permit auxiliarypressure to be expanded into the brakecylinder in the usual manner untilthere is a slight preponderance on the right or'trainpipe side ofservice-piston a, when the latter will move slowly to the left until thegraduating-valve a? is seated, at which point its further motion will bearrested by the resistance of the slide-valve a, and pressure will beheldin both brake-cylinder and auxiliary reservoir. During theseoperations ports ct and c are closed by service-valve a. Restoration ofnormal train-pipe pressure forces pistona and valve, Ct to normalposition, effecting the release of brake-cylinder pressure through portsd and a y In an emergency application of brakes a sudden reduction ofsome ten or twelve pounds is made in the train-pipe, which is felt onthe under side of piston 1) before piston or is afiected by reason ofthelimitation of the port or passage 19 leading tothe latter, in

contradistinction to the unrestricted coinmu- V nication between thetrain-pipe and the former piston b, which is forced down byauxiliary-reservoir pressure acting through port 0, compressing spring12 and opening emergencyvalve 5 This will be immediately followed by afull stroke of piston a, compressing spring a opening the large port atat d for quick expansion of auxiliary-reservoir pressure into thebrake-cylinder, and closing port 0. Auxiliary-reservoir pressure willthus be cut off from the space above emergency-piston I), while upon thefull stroke of the latter pressure remaining above the same will bereleased through leakage-groove b, whereupon spring b will force theemergency pis+ ton and valve to normal position.

The closure of emergency-valve 12 previous to and without any dependenceupon the resl ervoirs or expansion-chambers have been used, asheretofore, to actuate emergencyvalves the total fluid-pressure space oneach car has been necessarily correspondingly enlarged, resulting inincreased pumpwork on the locomotive and other undesirable features, allof which are eliminated by the use of auxiliary-reservoir pressurewithout opportunity for leakage during either service or emergencyapplication of brakes, as herein described. Further, in quick-actiontriple valves in general use the emergency piston and valve are actuateddirectly or indirectly by the service-valve and must therefore await itsmovements, while in my improved valve the emergency parts are firstactuated and are in no wise dependent on the proper operation of theservice-valve in applications of brakes, the result naturally being amore speedy and certain transmission of the emergency impulse to therear of a long train-pipe than can be accomplished by ordinary types ofquickacting triple valves.

By connecting port 19 and pipe D, as shown in Fig. 2, and limiting theservice-piston to its shorter range of stroke it will be readily seenthat the improved emergency mechanism herein described may be usedequally well in the more common form of quick'acting triple valve, whichreleases train-pipe pres sure to the brake-cylinder in emergencyapplications of the brakes. This limiting of the service-piston to itsshorter or service range of stroke may be accomplished by the meansillustrated, consisting of the threaded plug 6, which may be screwed inuntil its head rests against the end of the stem carrying abutment aThus when the piston strikes the abutment it is there stopped and port0. does not reach port (2. In the withdrawn position the head of plugeacts as a valve to prevent leakage of air.

the wheels of the first fifteen or twenty cars,

while ofiering no opposition to the rapid serial actuation of all thebrakes, thus enabling the full pressure of the auxiliary reservoirs tobefelt on the brake-pistons of the entire train at practically the sameinstant. ent practice the forward brakes are fully applied before thebrake-pistons of the rear cars are moved, frequently resulting in severeshocks, pulling out of draw-bars, injury to car-lading, &c. Thepractically simultaneous application of brakes on long trains at maximumpressure prevents such shocks and enables smooth and exact stops to bemade. Hence on long trains fitted with my improved valve the operativeswill set the plug 6 in on a number of cars at the forward end. Then incase of emergency applications the valves on those forward cars willgive the full serial venting, but their brakes will not go on until therear cars have felt the impulse, when all are applied substantiallysimultaneously.

While I have described and shown a form of quick-action triple valve,using a double stroke of its service -piston in service and emergencyapplications, respectively, it is evident that where a compoundservice-piston is used, as in certainforms of such valves well known inthe art, the feature of retarding application of forward brakes on longtrains, as herein described, may be availed of, and I therefore do notlimit myself in this respect to any specific form of triple valve or toany specific means of retarding the flow of auxiliary pressure tothebrake-cylinder.

Having thus described my invention, I claim- 1. In a fluid-pressurebrake system, the

combination with an auxiliary reservoir, and brake-cylinder, of aquick-action train-pipedischarge valve normally exposed toauxiliary-reservoir pressure on one side and to train-pipe pressure onthe other, a servicepiston having two lengths of stroke, and means forlimiting the movement of said service-piston to its shorter orpreliminary traverse in emergency applications of brakes, substantiallyas described.

2. In a fluid-pressure brake system, the combination of a service-pistonhaving two lengths of stroke with means for limiting the movement ofsaid piston to its first or preliminary traverse, regardless of theamount of reduction of train-pipe pressure, substantially as described.

In witness whereof I subscribe my signa ture in presence of twowitnesses.

WILLIAM H. CLARKE.

Witnesses:

WM. A. ROSENBAUM, GEO. S. KENNEDY.

In the pres

